Coffee is one of the most popular and safest stimulants that we consume. But during pregnancy, and potentially even when planning a pregnancy, it is one ‘legal drug’ where advice for women becomes a little more prescriptive. Alcohol, soft cheeses, raw fish and even raw sprouts are all foods that are best to limit or avoid during pregnancy. So, should coffee be added to the list and if so, how much is a safe amount to drink? That’s what I’ll dive into in this blog post.
Brew, java, black gold or go juice. Whatever you call it, coffee is the world’s second most popular beverage after tea. It has been estimated that over 2.2 billion cups of coffee are drunk every day.
So what’s in your daily caffeine hit? Coffee contains several useful nutrients. These include riboflavin, niacin, potassium, magnesium, various antioxidants, and many other natural plant chemicals. One estimate puts coffee as providing more antioxidants in a typical United States diet than the average person gets from their fairly minimal consumption of fruits and vegetables combined.
But any talk about coffee needs to profile the star of the show: caffeine.
Caffeine in your body
Caffeine is the most widely used psychoactive substance in the world. And I’m talking about both legal and illegal substances here. In Western society, 80 percent of the adult population consumes caffeine in amounts large enough to affect the brain. Soft drinks, tea and chocolate all contain caffeine, but coffee is the biggest source.
In your brain, caffeine blocks the function of an inhibitory neurotransmitter called adenosine. By blocking adenosine, caffeine increases brain activity and releases other neurotransmitters like norepinephrine and dopamine. This reduces tiredness and makes you feel more alert.
This all means that caffeine can lead to a short-term boost in brain function and mood, lower reaction time, increase vigilance and improve general cognitive function.
There are a surprising number of health benefits linked to regular coffee drinking: from a lower risk of developing type 2 diabetes right through to even helping people struggling with mobility issues from Parkinson’s disease. I won’t go into the full story here, but you can read the blog post I wrote on this topic for the full low down on the surprising health benefits of coffee.
But for this post, I want to narrow in on one specific question: could your daily coffee habit be hurting your chances of conceiving or even harming a developing foetus?
Caffeine and conceiving
I’ll start with the good news straight off the bat: if you are trying to conceive, then there is no need to go cold turkey on caffeine. But I do need to make a disclaimer that it is certainly wise and recommended to keep your coffee habit down to the equivalent of two cups of coffee per day. Let me explain why.
Cutting back on caffeine is common fertility advice given to women who are struggling to conceive or going through IVF. So, are there good grounds for this advice? If you go digging into the scientific research, you’ll find mixed messages. Some studies do find a link between caffeine and a woman’s ability to conceive, while others find that it has no impact. However, the quality of the research studies here are not the greatest.
A link between caffeine and fertility is plausible because caffeine is known to have effects on ovulation and hormone levels.
Another interesting theory is that caffeine can affect how the muscles in the fallopian tubes work. These muscles contract in smooth, rhythmic waves to help the egg on its way to the uterus. Caffeine could disrupt this movement and affect the journey of the egg to its destination.
The experts conclude that there just isn’t enough evidence to make a definitive conclusion about caffeine and fertility. But it is worth paying heed to the possibility and keeping your coffee habit dialled back when trying to conceive.
Caffeine and IVF
Advice about caffeine also applies to women undergoing IVF. One study from Denmark that looked at almost 1,700 women undergoing IVF at a large fertility clinic found that women who drank up to 5 cups of coffee had similar pregnancy success compared to women who drank no coffee.
Although previous work from this same research group did find that drinking more than five cups of coffee a day was linked to a lower chance of conception and having a live birth.
Coffee during pregnancy: yes or no?
So that’s the story about conception and caffeine. But once a woman is pregnant, the advice about caffeine becomes much stronger – and for good reason. A systematic review and meta-analysis from 2017 found a 37 percent higher risk of miscarriage in women who consumed more than 300 milligrams of caffeine a day. And the risk of miscarriage more than doubled with daily caffeine intakes above 600 milligrams.
Yet more research has also found that for women having more than 300 milligrams of caffeine each day during pregnancy, it is linked to foetal growth restriction which could result in low birth weight.
On a positive note at least, a major review on the adverse effects of caffeine on healthy adults, pregnant women, adolescents and children from 2017 found that for women who are pregnant, up to 300 milligrams of caffeine a day is considered safe. For non-pregnant adults, the safe limit goes up to 400 milligrams per day.
How much is too much?
None of the research I’ve profiled is new or surprising. A link between caffeine and the risk of miscarriage has been known for some time. Which is why Food Standards Australia and New Zealand recommend that for women who are pregnant or breastfeeding, daily caffeine consumption should not exceed 200 milligrams (that’s about two cups of coffee). The same advice is mirrored by European and US regulatory bodies that advise that during pregnancy, no more than 200 milligrams of caffeine should be consumed per day.
Exactly why too much caffeine could be an issue during pregnancy is likely because a woman’s ability to metabolise caffeine slows during pregnancy. What’s more, caffeine readily passes from the placenta to the growing baby which is not developed enough to inactivate it. So caffeine can accumulate in the baby’s body and brain and have a real development effect.
The advice on caffeine during pregnancy I’ve given from peak health bodies could be subject to revision in the future as more research becomes available. Some experts in the medical community argue that because there is a dose-dependent relationship between caffeine and pregnancy risk, it indicates that even lower doses below 200 milligrams per day could have an effect during pregnancy. So according to some experts, the recommendations for a safe threshold level should be lowered even further. Some even argue that women who are pregnant or trying to conceive should avoid caffeine altogether.
Where do you find caffeine?
Quite rightly we associate coffee with caffeine, but find caffeine in a range of drinks and foods. So, it is good to be aware of where it may lurk if you’re keeping an eye on a 200 milligrams per day limit.
Sources like tea, cola soft drinks, energy drinks, chocolate and coffee ice cream can all contain caffeine. Caffeine also shows up in herbal products and over-the-counter drugs, including some headache, cold, and allergy remedies. So read labels carefully.
As a rough guide, a can of an energy drink like Red Bull or V has 80 milligrams of caffeine. Black and green tea have about 50 milligrams while cola drinks have 35 milligrams in a 375 mL can. If you enjoy dark chocolate, then you’ll find about 40 milligrams of caffeine in a 50-gram serve.
Cutting your caffeine habit
If you have plans to conceive soon and your daily coffee ritual amounts to a lot more than two cups a day, then time is on your side to make the transition easier and minimise some of the withdrawal symptoms such as fatigue and headaches.
You might want to start by switching to a drink that’s half regular brew and half decaf. Or reduce the caffeine in homemade beverages by watering them down or brewing them for a shorter time. If you love to start your day with a cup of black tea, steeping your tea bag for one minute instead of five cuts the caffeine by as much as half.
What it all means
Coffee at this stage is not on the avoid list during pregnancy or when planning pregnancy. But there is enough evidence to support the case that for a short time in her life, a woman should make a concerted effort to keep her coffee habit in check.